I build payment and dispatch backends that stay correct under load. Most of my work has been making money movement idempotent, finding why queues fall behind, and writing incident reviews that change how the team works.
Our payout service occasionally paid a lender twice, about 30 times a month. I designed client-supplied idempotency keys, wrote the migration for two years of payout records and rolled it out behind a flag. Duplicates went to zero the next quarter.
github.com/amorgan/payout-keys-notesConsumer lag hit 40 minutes during the holiday peak. I traced it to one hot partition keyed on warehouse ID and re-keyed by route. Lag stayed under two minutes for the rest of the season.
I wrote the review within two days. Two of its five actions became team defaults, including no deploys on settlement days.
fernway.dev/blog/march-reviewRan the payments rotation for two years. Cut alert rules from 60 to 14 and pages from about 9 a week to 3.
Built a CLI finance uses to pull monthly ledger exports. It replaced a three-hour spreadsheet job.